Li Z B, Wachtell K, Okin P M, Gerdts E, Liu J E, Nieminen M S, Jern S, Dahlöf B, Devereux R B
Department of Medicine, Weill Medical College of Cornell University, New York, NY 10021, USA.
J Hum Hypertens. 2004 Jun;18(6):397-402. doi: 10.1038/sj.jhh.1001709.
Electrocardiographic (ECG) left bundle branch block (LBBB) is associated with left ventricular hypertrophy (LVH), but its relation to left ventricular (LV) geometry and function in hypertensive patients with ECG LVH is unknown. Echocardiograms were performed in 933 patients (548 women, mean age 66+/-7 years) with essential hypertension and LVH by baseline ECG in the Losartan Intervention For Endpoint reduction in hypertension (LIFE) study. LBBB, defined by Minnesota code 7.1, was present in 47 patients and absent in 886 patients. Patients with and without LBBB were similar in age, gender, body mass index, blood pressure, prevalence of diabetes, and history of myocardial infarction. Despite similarly elevated mean LV mass (126+/-25 vs 124+/-26 g/m(2)) and relative wall thickness (0.41+/-0.07 vs 0.41+/-0.07, P=NS), patients with LBBB had lower LV fractional shortening (30+/-6 vs 34+/-6%), ejection fraction (56+/-10 vs 61+/-8%), midwall shortening (14+/-2 vs 16+/-2%), stress-corrected midwall shortening (90+/-13 vs 97+/-13%) (all P<0.001), and lower LV stroke index (38+/-7 vs 42+/-9 ml/m(2)) (P<0.05). Patients with LBBB also had reduced LV inferior wall and lower mitral E/A ratio (0.75+/-0.18 vs 0.87+/-0.38) (all P<0.05). The above univariate results were confirmed by multivariate analyses adjusted for gender, age, blood pressures, height, weight, body mass index, heart rate, and LV mass index. Among hypertensive patients at high risk because of ECG LVH, the presence of LBBB identifies individuals with worse global and regional LV systolic function and impaired LV relaxation without more severe LVH by echocardiography.
心电图（ECG）左束支传导阻滞（LBBB）与左心室肥厚（LVH）相关，但在心电图显示左心室肥厚的高血压患者中，其与左心室（LV）几何形态及功能的关系尚不清楚。在氯沙坦干预降低高血压终点事件（LIFE）研究中，对933例原发性高血压且基线心电图显示左心室肥厚的患者（548例女性，平均年龄66±7岁）进行了超声心动图检查。根据明尼苏达编码7.1定义的左束支传导阻滞存在于47例患者中，886例患者不存在。有和没有左束支传导阻滞的患者在年龄、性别、体重指数、血压、糖尿病患病率及心肌梗死病史方面相似。尽管平均左心室质量（126±25 vs 124±26 g/m²）和相对室壁厚度（0.41±0.07 vs 0.41±0.07，P=无显著性差异）同样升高，但有左束支传导阻滞的患者左心室缩短分数较低（30±6 vs 34±6%）、射血分数较低（56±10 vs 61±8%）、室壁中层缩短率较低（14±2 vs 16±2%）、应力校正室壁中层缩短率较低（90±13 vs 97±13%）（均P<0.001），且左心室每搏输出量指数较低（38±7 vs 42±9 ml/m²）（P<0.05）。有左束支传导阻滞的患者左心室下壁也减小，二尖瓣E/A比值较低（0.75±0.18 vs 0.87±0.38）（均P<0.05）。上述单变量结果经对性别、年龄、血压、身高、体重、体重指数、心率及左心室质量指数进行校正的多变量分析得到证实。在因心电图显示左心室肥厚而处于高危状态的高血压患者中，左束支传导阻滞的存在可识别出整体和局部左心室收缩功能较差且左心室舒张受损但超声心动图显示左心室肥厚并不更严重的个体。
